U.S. Pat. No. 4,551,959 of Schmid discloses a building block with two spaced supportive parts separated from one another by a quantity of insulating material positioned between the parts. At column 2 of his patent, Schmid discloses that his insulating material 54 is foamed in place. He states that: ". . . to assemble the block 10 with foam in place insulation, the block parts . . . are initially arranged in their desired spaced relation relative to one another and subsequently held in such relation while the insulating material, in its uncured condition, is directed into the space between the block parts. . . . After filling the space with the foam insulation and allowing it to cure to a hardened condition, any excess insulation can be cut or trimmed away as desired."
The process of the Schmid patent is not commercially practical. In the first place, the foam material, prior to the time it is cured, acts as an adhesive; and the block/foam structure thus tends to adhere to the pallet on which the block is sitting. In the second place, the rate of curing of the polyurethane foam is very dependent upon factors such as temperature, relative humidity, and barometric pressure; inasmuch as most block manufacturing plants do not carefully control these variables, it is difficult to consistently obtain building blocks having uniform properties with the process of Schmid. In the third place, where it is desired to have the foam extend beyond the surface(s) of the cement block, one must overfoam and subsequently cut the foam to size (a labor- intensive activity) and/or utilize a form which will help shape the foam to the required dimensions. In the latter instance, however, the foam tends to stick to the form.
In addition to the process of Schmid being commercially impractical and relatively expensive, the block produced by such process suffers from some major disadvantages. The two parts of the building block of the Schmid patent are held together by insulating material between such parts. When Schmid's block is subjected to conditions which will tend to degrade and/or weaken the insulating material (such as those one might encounter in a fire), the Schmid block will tend to lose its structural integrity.
It is an object of this invention to provide an insert which may be used to produce a building block.
It is another object of this invention to provide a process for preparing a building block which does not require that the block's insulating portion be foamed in place.
It is yet another object of this invention to provide a process for preparing a building block which does not require that excess insulator material be trimmed or cut from the formed block.
It is yet another object of this invention to provide a process for preparing a building block which produces a block with good structural integrity that does not contain thermally conductive webs or bridges between its wythes which allow the flow of heat from one wythe to another.
It is yet another object of this invention to provide a process for preparing a building block that will retain its structural integrity when the insulating material in it is weakened or destroyed.
It is yet another object of this invention to provide a process for preparing a building block which produces a block with improved sound insulating properties.
It is yet another object of this invention to provide a process for preparing a building block which produces a block with improved heat storage properties.
It is yet another object of this invention to provide a process for preparing a building block which produces a block which, when joined with mortar to building blocks of similar construction, will provide a construction wall which is less likely to crack when subjected to stress from earthquakes than prior art construction walls.
It is yet another object of this invention to provide a process for preparing a building block with improved moisture resistance.
It is yet another object of this invention to provide a structure comprised of the building block of this invention and at least one reinforcing rod.
It is yet another object of this invention to provide a process for the production of a building block which tends to resist the passage of Radon gas through its structure.
It is yet another object of this invention to provide a manufacturing process in which an insert may be used in place of a mold and the insert becomes an integral part of the molded product.
It is yet another object of this invention to provide an improved building block.